Convert from any base to decimal and vice versa | C # program to convert a number from any base to decimal ; To return value of a char . For example , 2 is returned for '2' . 10 is returned for ' A ' , 11 for ' B ' ; Function to convert a number from given base ' b ' to decimal ; Initialize ; power of base Initialize result ; Decimal equivalent is str [ len - 1 ] * 1 + str [ len - 2 ] * base + str [ len - 3 ] * ( base ^ 2 ) + ... ; A digit in input number must be less than number 's base ; Driver code
using System ; class GFG { static int val ( char c ) { if ( c >= '0' && c <= '9' ) return ( int ) c - '0' ; else return ( int ) c - ' A ' + 10 ; } static int toDeci ( string str , int b_ase ) { int len = str . Length ; int power = 1 ; int num = 0 ; int i ; for ( i = len - 1 ; i >= 0 ; i -- ) { if ( val ( str [ i ] ) >= b_ase ) { Console . WriteLine ( " Invalid ▁ Number " ) ; return - 1 ; } num += val ( str [ i ] ) * power ; power = power * b_ase ; } return num ; } public static void Main ( ) { string str = "11A " ; int b_ase = 16 ; Console . WriteLine ( " Decimal ▁ equivalent ▁ of ▁ " + str + " ▁ in ▁ base ▁ " + b_ase + " ▁ is ▁ " + toDeci ( str , b_ase ) ) ; } }